mar345

Bax

I just converted my troublesome FS 120II pumper to an OS FS120E. Basically it's a replacement of the crankshaft, backplate and carb pump assembly. Once I received the parts it only took an hour or so to complete. However during the dissassembly I noticed that there was no cylinder head gasket between the top of the cylinder liner and the cylinder head on the old FS 120II. Upon reassembly the parts mesh well , the valve clearances are the same and compression feels good. On the parts breakdown diagram of the FS 120E a cylinder head gasket is shown. I don't have an exploded view of the FS 120II parts assembly so don't know if it was suppossed to have a cylinder head gasket or not. So, my question is , do I need to install a cylinder head gasket to complete the conversion?
Thanks,
MAR

Wulf

My Feedback: (5)

I have one of these engines ,what was the problem??-How come you did`nt like the pump??

mar345

Wulf,

The old pumped OS 120II doesn't suit my style of flying which is only occassionally. If the engine sits idle for a few weeks it may require 24 to 32 ounces of fuel through it before the diaphraghm in the regulator loosens up for proper fuel pressure regulation. Until that happens one may experience poor throttle transition, rich mid range, poor idle reliability, etc, etc. My other non pumped engines are very reliable and once tuned need little or no adjustment. For its intended purpose of frequent use and F3a flying it was a fine engine. But for a Scale flyer who may only fly the same model but only once a month or so and wants to crank up the engine and go without a lot of fiddling around, not so good. So I converted to the non pumped version OS FS120E.

Wulf

My Feedback: (5)

Thanks for the info I was planning on using mine in my Pica 1/6 scale Mustang--I figured the pumped version would be the nuts for realiablity--I want a reliable engine in this one seeing it`ll have all the goodies on her ,flaps, retracts etc.Oh well back to the drawing board--Is there anyway to keep diaphram lubed up so this problem is alimminated?

Bax

My Feedback: (11)

There most certainly is a cylinder head gasket in your O.S. FS-120 Surpass engine. It is of the same color of metal that is the cylinder head. It's a soft shim that is fitted into the groove that accepts the cylinder liner, and it very close-fitting in the groove. Use of a very sharp knife point or a pin will enable to to grab an edge and carefully lift it. Please be careful, since once it's bent, it's useless.